There are always one or two people in any big NBA discussion who think (or at least consider) that the league fixes games. Right from the get-go this appears to be a wild idea, but let's take a deeper look at what fixing would actually look like and why the NBA would or wouldn't do it.
The first thing to discuss is the risk-reward factor for the NBA in regards to "fixing" games. Let's say ensuring a Game 7 in the NBA Finals. What is their reward? One extra game of ticket sales, a fair amount of additional advertising, and a ton of people watching the final game on television. Will all that add up to a decent chunk of revenue? Yes, it certainly will. But compared to all the playoff games, plus an 82 game season, and the All Star break activities, and the Christmas games...... it is still nice, but not a game-changer. The risks on the other hand?
The risk for the NBA if they were to be caught fixing games is huge. People watch the NBA (and most other sports) because they don't know who is going to win, because the team they root for could theoretically have a chance on any given night against their opponent. If fans found out the games were rigged, the outrage would be absolutely astounding. The product would be considered fake, and all results throughout the NBA's history would have to be questioned. It would undermine the entire fabric of the NBA.
If substantiated reports came out that the NBA was illegally influencing the outcome of games, the league would be over. Fans would quit in droves, sponsorships would be taken off, and the athletes themselves might revolt. There would be no coming back for the NBA. The reward of solid additional revenue (albeit a drop in the bucket compared to overall NBA earnings) against a risk of complete annihilation and loss of billions and billions of dollars? I think it would be a stupendously foolish decision for the NBA to fix their games, and I am sure that they recognize this (taking all moral quandaries of if they even want to fix them aside).
What if you think the reward is greater than I believe, or the risk less? Well, there is still the issue of how exactly the league would influence the games. Do they tell the refs to favor a certain team or player? How would they inform these people? Email? Text message? Perhaps a secret meeting in an underground labyrinth? There is simply no reliable way to fix the league without involving a lot of people. And the more people are brought in, the more likely it is for someone to spill the beans. Simply put, if the NBA were to ever decide a game, the news would come out, and it would be exposed very, very quickly. There is no way to keep it a secret, not for an extended amount of "fixing" anyway.
It's understandable for fans to get frustrated when calls go against their team. And even more so for the players and teams involved. But there is absolutely no evidence of the league being fixed, nor is there a good reason for the NBA to even attempt to do so. Are some referees biased against certain players or teams? It's certainly possible. Might some of them even be pulling a Tim Donaghy and making calls to work in favor of gambling or the game spread? Unlikely, but not out of the realm of reality. A whole, NBA-wide conspiracy, on the other hand, is nonsensical. It isn't unreasonable to think the NBA might prefer certain teams to win games, series, or even the championship in order to improve their bottom line. But it is unreasonable to think they would act on it. Show me the evidence or stand down.